<!doctype html>
<html>
<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="Content-Security-Policy" content="upgrade-insecure-requests">
    <title>Welcome😁</title>
    <link rel="icon" href="favicon.png" sizes="16x16" type="image/png">

    <style>
        html, body {
            width: 100%;
            height: 100%;
            display: flex;
            align-items: center; /*垂直居中*/
            justify-content: center; /*水平居中*/
        }

        .textshow {
            text-align: center;
            font-size: 50px;
        }
    </style>
    <script>
        window.onload = function(){
            //setInterval('changeIcon()', 800);
        }
        function changeIcon(){
            var f = document.querySelector('link[rel="icon"]');
            if (f.href.indexOf("favicon.png") > -1){ f.href = "favicon2.png"; }
            else if (f.href.indexOf("favicon2.png") > -1){ f.href = "favicon.png"; }
        }
    </script>
</head>
    <body>
        <div class="textshow">
            Welcome
        </div>
    </body>
</html>
